1. Field of the Invention
The present invention relates to transformers.
2. Description of the Related Art
Transformers are used to transform one voltage into another. One application for transformers is in an electric vehicle. There, the power source for the vehicle, the "traction batteries", typically has a voltage of several hundred volts. However, conventional electrical and electronic accessories on the vehicle are designed to operate at a nominal voltage of 12 volts. A DC-to-DC converter containing a transformer is used to step the traction battery voltage down to a nominal 12 volts. In such an application, the transformer must be capable of supplying large currents, typically several tens of amperes.
Transformers for this type of high-current application are typically designed with windings made of copper foil. Several turns of copper foil are wound around the magnetic core of the transformer in a painstaking and expensive process. At appropriate places on the foil windings, braided conductors are soldered. These braided conductors are then connected to terminals of the transformer. Soldering the braided conductors onto the foil and onto the terminals are also slow, and therefore expensive, processes.
An additional concern in a typical transformer is that one of the foil windings will electrically short to itself or to another of the foil windings. This concern is due to burrs which are typically left on the foil when it is fabricated. Although the foil is insulated with, for example, plastic film before being wound to form the coils of the transformer, burrs left on the foil can pierce the insulation and nonetheless cause short circuits.
In light of the difficulties encountered in fabricating a conventional transformer, a transformer design which lends itself to fabrication in a more convenient way will provide cost advantages over the prior art. Further, a transformer design which is less apt to having short circuits will provide quality advantages over prior art designs.